1. Field of the Invention
The present invention relates to an AC (alternating current) drive type plasma display device having its feature in a dielectric layer, and a manufacturing method thereof.
2. Description of the Related Art
As a image display device which replaces a currently mainstream cathode ray tube (CRT), various types of flat type (flat panel type) display devices have been considered. Examples of such flat type display devices are a liquid crystal display (LCD), an electroluminescence display device (ELD), and a plasma display device (PDP: plasma display panel). Among them, the plasma display device has advantages in that it may be relatively easy to provide a large-sized screen and having a wide viewing angle; in addition, such display devices have satisfactory resistance to environmental factors, such as temperature, magnetic effects, vibration, etc. and has a prolonged lifetime, so that it is expected to be applied not only to flat television sets to be hanged on a wall for household use but also to large-scaled information terminal apparatuses for public use.
The plasma display device is a display device that obtains luminescence by applying voltage to a discharge cell containing discharge gas including rare gas within its discharge space so as to excite a phosphor layer in the discharge cell by means of an ultraviolet ray generated based on a glow discharge in the discharge gas. In other words, each discharge cell is driven by a principle similar to that of fluorescent light, discharge cells usually gather on the order of hundreds of thousands so as to constitute one display screen. Plasma display devices are roughly classified into a direct current drive type (DC type) and the alternating current drive type (AC type) according to the method of applying voltages to the discharge cells. Each type has advantages and disadvantages. The AC type plasma display device requires only forming a barrier rib in form of a stripe, for example, which plays the role of partitioning each of the discharge cells within the display screen, therefore it is suitable for high definition. As the surface of an electrode for discharge is coated with a protective layer made of a dielectric material, the electrode cannot be easily worn out, therefore it has the advantage of a prolonged lifetime.
As an example of the AC type plasma display device, a three-electrode type plasma display device shown in Japanese Patent Laid-Open No. H5-307935 and Japanese Patent Laid-Open No. H9-160525, for example.
The dielectric layer made from a dielectric material such as a low-melting point glass paste is provided at a display surface side panel in such an AC type plasma display device. Such a dielectric layer is usually formed by means of a screen printing process. In the drive of the AC type plasma display device, an electric charge is accumulated in the dielectric layer, and the accumulated charge is released by applying a reverse voltage to a discharge sustain electrode so as to generate plasma. In order to make an electric charge distribution as even as possible, the dielectric layer is needed to be even and homogeneous. In addition, preferably the dielectric layer is a finely structured layer from a viewpoint of improving dielectric withstanding voltage and from a viewpoint of damage prevention of the discharge sustain electrode located thereunder. Moreover, from a viewpoint of an improvement in luminance, a thickness of the dielectric layer should be preferably as thin as possible.